shopify-wishlist.js

const wishlistApi = async ({req, res, shopifyAccessToken, shopifyDomain, allowedOrigins, metafieldNamespace, metafieldKey}) => {
  const shopifyAdminConfig = {
    Accept: 'application/json',
    'Content-Type': 'application/json',
    'X-Shopify-Access-Token': shopifyAccessToken,
  };
  const apiVersion = '2022-07'

  const preparePayload = (query, variables) => ({
    query,
    variables,
  });

  const CUSTOMER_QUERY = `
    query customerQuery($email: String!) {
      customers(first: 1, query: $email) {
        edges {
          node {
            id
            metafield(namespace: "${metafieldNamespace}", key: "${metafieldKey}") {
              id
            }
          }
        }
      }
    }
  `;

  const METAFIELD_DELETE_MUTATION = `
    mutation metafieldDelete($input: MetafieldDeleteInput!) {
      metafieldDelete(input: $input) {
        deletedId
        userErrors {
          field
          message
        }
      }
    }
  `;

  const CUSTOMER_UPDATE_MUTATION = `
    mutation customerUpdate($input: CustomerInput!) {
      customerUpdate(input: $input) {
        customer {
          id
        }
        userErrors {
          field
          message
        }
      }
    }
  `;

  // we pass an array of origin strings in allowedOrigins. If it matches, we set the CORS header
  if (allowedOrigins.includes(req.headers.origin)) {
    res.setHeader('Access-Control-Allow-Origin', req.headers.origin);
  }

  // (1) call customer to get customer id for customer update mutation
  // (2) call metafieldDelete to remove metafield if it already exists (because we cannot overwrite metafield)
  // (3) call customer update mutation to update metafielfd
  let input;

  try {
    input = JSON.parse(req.body);
  } catch (error) {
    // eslint-disable-next-line no-console
    console.error('JSON parsing error when trying to set customer wishlist:', error);
    return res.status(400).json({ error: 'Bad request body' });
  }

  if (!input?.wishlist || !input?.email) {
    return res.status(400).json({ error: 'Bad request body' });
  }
  let customerId;
  let metafieldId;

  const payloadCustomer = preparePayload(CUSTOMER_QUERY, {
    email: `email:${input.email}`,
  });

  try {
    const customerRes = await fetch(
      `https://${shopifyDomain}.myshopify.com/admin/api/${apiVersion}/graphql`,
      {
        method: 'POST',
        headers: shopifyAdminConfig,
        body: JSON.stringify(payloadCustomer),
      }
    );

    if (customerRes.ok) {
      const { data: customerData } = await customerRes.json();
      customerId = customerData.customers.edges[0]?.node.id;
      metafieldId = customerData.customers.edges[0]?.node.metafield?.id || null;

      if (!customerId) {
        return res.status(500).json({ error: 'Cannot find customer' });
      }
    }
  } catch (error) {
    return res.status(500).json({ error: error.message });
  }

  if (metafieldId) {
    const payloadDeleteMetafield = preparePayload(METAFIELD_DELETE_MUTATION, {
      input: {
        id: metafieldId,
      },
    });
    try {
      const metafieldRes = await fetch(
        `https://${shopifyDomain}.myshopify.com/admin/api/${apiVersion}/graphql`,
        {
          method: 'POST',
          headers: shopifyAdminConfig,
          body: JSON.stringify(payloadDeleteMetafield),
        }
      );

      if (!metafieldRes.ok) {
        return res.status(500).json({ error: 'Failed to set customer wishlist' });
      }
    } catch (error) {
      return res.status(500).json({ error: error.message });
    }
  }

  const payloadMutateCustomer = preparePayload(CUSTOMER_UPDATE_MUTATION, {
    input: {
      id: customerId,
      metafields: [
        {
          namespace: metafieldNamespace,
          key: metafieldKey,
          value: JSON.stringify(input.wishlist),
          type: 'json',
        },
      ],
    },
  });

  try {
    const customerRes = await fetch(
      `https://${shopifyDomain}.myshopify.com/admin/api/${apiVersion}/graphql`,
      {
        method: 'POST',
        headers: shopifyAdminConfig,
        body: JSON.stringify(payloadMutateCustomer),
      }
    );

    if (customerRes.ok) {
      const { data: customerData } = await customerRes.json();
      return res.status(200).json({ customer: customerData });
    }

    return res.status(500).json({ error: 'Failed to set customer wishlist' });
  } catch (error) {
    return res.status(500).json({ error: error.message });
  }
}

export default wishlistApi;